1916. No. 10. THE LOWER CAMBRIAN HOLMIA FAUNA. I9 



Temten. The piece also contains remains of Holmio Kjendfi Lnrs. and 

 Obolella rotuttdata nov. sp. 



Observations: Like the foregoing specimen, this also differs from 

 a typical Sc^fiella, the apex being somewhat nearer the anterior margin 

 than is common in the latter genus. It is evidently different from Scettella 

 aniiqua nov. sp. being lower and ha\-ing a quite different profile; the 

 sculpture also differs. It approaches the form that Lixnarssox described 

 from the exulans limestone under the name Metoptoma Barrandei^. The 

 margin of the latter, however, is more ovate and the profile is diflerent. 

 Although evident]}- different, there are also various points of resemblance 

 to Scettella rctiadata Billings from the Etcheminian in Newfoundland and 

 Massachusetts. 



-As several of the Cambrian Palaeactttidae exhibit very considerable 

 variation with regard to the form of the shell, it would be of great 

 interest to procure a more extensive material both of the present and the 

 foregoing species. It is conceivable that they might be combined with a 

 series of variations. 



Helcionella ragosa Hall. 

 iPl. II, figs. 3, 3 a — b.i 



Of the widely extended and gready varying Lower Cambrian form 

 Stenotheca nigosa H.all, for which Grab.au and Shimer made the new 

 genus Helciottella, I have found only two specimens in my material, these 

 differing considerabh' from each other. One of them, which will be de- 

 scribed here, is unfortunately so badly preserved that it cannot be dealt 

 with Completel}-. It is a somewhat strong specimen, the shell having a 

 height of about 6 mm. The apex is slightly prominent and the anterior 

 side ver}' steep. Fig. 3 and the two attempts at reconstruction 3 a — b 

 represent the most important characters as well as is possible under the 

 circumstances. The portion preserved presumably represents only the 

 inner mould of the shell; we therefore do not see anything of the sculp- 

 ture of the shell, but only indistinct, broad, cross furrows that are most 

 marked on the posterior region. 



Occurrence: One specimen, very impertect. was found with 

 Scetulla antiqiia nov. sp. in a loose piece of typical StreiineHa limestone 

 at Temten. 



^ G. LiXN.\R5SON, Om faunaen i kalken med Conocoryphe exulans (Sveriges Geol. Unders. 

 Ser. Ç No. 35, 1870, pag. 241. 



